1. Field of the Invention
This invention relates generally to an improved portable hand-held VHF survival radio that can broadcast and receive audio information, and specifically to an improved portable hand-held radio having a waterproof, lightweight, sealed housing assembly that can withstand extremely diverse ambient pressure environments while remaining waterproof. The invention includes an improved housing assembly that has a sealed front and rear housing, a vent plug for ambient pressure exchange and equalization that is waterproof, and a sealed flexible panel for actuation of the mechanical switches. The radio also includes an improved holding strap that fits onto the housing, and an automatic power turn off switching circuit.
2. Description of the Prior Art
The use of portable hand-held VHF survival radios is well known. Battery operated VHF transmitters and receivers for use in the water or on a life raft in an emergency for communication with search and rescue personnel have been known for many years. The most important aspect of a survival radio is reliability. The radio must withstand long periods of inactive storage. Also, the radio must be able to be subjected to diverse ambient atmospheric pressures in view of possible unpressurized transport of such survival equipment in aircraft at altitudes up to 50,000 feet without structural failures. Any damage to the waterproof seal of the housing assembly could expose the radio interior broadcast and receiver circuitry and batteries to moisture, or worse, if used in the water or a life raft, to surrounding water, which could immediately permanently damage the interior circuitry, disabling the survival radio. Therefore, structural integrity is essential to the reliability of a dependable survival radio.
Another problem in prior survival radios that affects overall reliability for long storage periods can be moisture intrusion. Mechanical switches typically have shafts that protrude through the radio housing assembly for operation of the transmitter, channel selection, and volume, which must connect to the circuitry without exposing the housing assembly contents to moisture with effective long term seals. Also, the use of plastic housing assemblies requires split molds and split housing pieces that ultimately have to be tightly sealed together. Finally, transport of sealed waterproof plastic housing assemblies in jet aircraft result in equipment being subjected to extremely low ambient pressures which could often result in cracks or seal ruptures in the housing assembly, destroying the moisture-proof capability.
The primary purpose of the present invention is to provide a portable, hand-held VHF survival radio that has a radically improved structural housing assembly that is waterproof to at least 1 meter, while allowing for its exposure to very low ambient air pressure, such as may be found at 50,000 feet in an aircraft, without any degradation of the equipment's reliability or waterproof capabilities. Also, the present invention has improved manual switching which utilizes a deformable sealed flexible panel so that exterior manual switching of internal circuitry can be accomplished without switch connectors through the housing assembly wall. The radio housing assembly has a front housing and a rear housing, which are permanently joined together by an improved seal that insures that the housing assembly, once joined together, will not leak or come apart. The hand-held portable unit also includes, attached to the housing, an improved strap for two modes of utilization of the device, and an automatic power off circuit to protect the longevity of the power source.